the effect of different severities of diet dilution and using a supplemental enzyme on performance of broiler chickens

in this study the effect of diet dilution in 16-20 d of age and using a multi-enzyme (endofeed-w) on performance, carcass characteristics and some blood parameters of broiler chickens (cobb 500, commercial strain) was studied. this experiment was conducted as a factorial arrangement 2×3 in a completely randomized design with 3 replicates and 8 chicks in each replicate. experimental diets contained 0, 20 and 40 percent rice hulls and 2 levels of enzyme (0, 500 mg/kg). these diets contained 3000, 2400, 1800 kcal/kg metabolizable energy, and 21, 16.8 and 12.6 % crude protein, respectively. in other days of experiment, the chicks were fed in according to cobb 500 rearing guideline. during feed restriction and whole period of rearing (1-44d), diet diluting up to 20% decreased feed conversion ratio (p<0.05). adding enzyme to experimental diets decreased feed intake and feed conversion ratio in whole period of experiment (p<0.05). chickens fed with treatment 2 (without rice hulls, 0.05% supplemental enzyme) had the lowest feed intake and feed conversion ratio in whole period of the experiment. results showed that diet diluting up to 20 % during 16-20 d of age, with or without endofeed-w supplemental enzyme had no adverse effect on broiler chickens performance.